1. Field of the Invention
This invention is directed to the winding of flexible material in a universal figure-8 pattern around a mandrel, and in particular to such windings in which a crossover is formed in all but one location so as to generate a payout hole extending from the exterior of the winding to the interior axial opening therein and wherein the gain of the winding, defined as the ratio of the speed of traverse to the speed of the spindle, is varied in either a positive or negative manner so as to increase the density of the wind by displacing the crossovers with respect to one another.
2. Prior Art
The winding of flexible material about a mandrel with successive figure-8s spaced radially around the mandrel and with a radial opening extending from the exterior of the winding to the interior core thereof is known from U.S. Pat. Nos. 3,178,130 and 4,406,419 assigned to the assignee of the present invention. The figure-8s are spaced such that the crossovers exist in all but one location and the absence of the crossovers is the location of the payout hole. In the case of a one wind, the spindle travels at a given speed and its traverse is travelling exactly one-half the spindle speed, and all crossovers of the figure-8s will be in the same place. The winding as defined in the aforementioned patent, as well as U.S. Pat. No. 3,666,200, which is also assigned to the assignee of the present application, is satisfactory with regard to relatively small diameter winds in which the flexible material being wound is of relatively small diameter. However, as the diameter of the wind is increased and the diameter of the flexible material being wound is of relatively large diameter, the location of the crossovers at the same place in the winding results in an inefficient winding, i.e., one that is less dense and which has a high crest and valley produced in the wind.
U.S. Pat. No. 3,666,200 suggests the variation of the gain of the wind such that the crossovers of the figure-8s are displaced with respect to one another in order to obtain a more compact and more dense wind. However, there is a necessity to improve the method of winding flexible material for large diameter winds especially in the instances where relatively large diameter flexible material is being wound. Additionally, it is common practice to compress a winding wound in accordance with the teachings of the aforementioned prior art patent to make the winding density more uniform such that the finished winding can be packaged in a smaller box.